The average marks of the first 12 students in a class was 33, and the average marks of the next 8 students of the class was 45. What is the average marks of the class? (correct to one decimal place)

Correct option is C

Given:
Average of first 12 students = 33
Average of next 8 students = 45
Total students = 12 + 8 = 20
Formula Used:
Average = (Sum of all observations) ÷ (Number of observations)
Solution:
Sum of marks of first 12 students = 33 × 12 = 396
Sum of marks of next 8 students = 45 × 8 = 360
Total marks = 396 + 360 = 756
Average marks of the class= 756 ÷ 20= 37.8